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Fix SHA-256-based KDF when using CCMP as the pairwise cipher

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IEEE 802.11r KDF uses key length in the derivation and as such, the PTK
length must be specified correctly. The previous version was deriving
using 512-bit PTK regardless of the negotiated cipher suite; this works
for TKIP, but not for CCMP. Update the code to use proper PTK length
based on the pairwise cipher.

This fixed PTK derivation for both IEEE 802.11r and IEEE 802.11w (when
using AKMP that specifies SHA-256-based key derivation). The fixed
version does not interoperate with the previous versions. [Bug 307]
This commit is contained in:
Jouni Malinen 2009-04-01 12:04:36 +03:00 • committed by Jouni Malinen
parent d61f48ba1d
commit c0a6190815
8 changed files with 28 additions and 18 deletions
Download patch file Download diff file Expand all files Collapse all files

5
src/rsn_supp/wpa.c
View file

@ -360,14 +360,15 @@ static int wpa_derive_ptk(struct wpa_sm *sm, const unsigned char *src_addr,
const struct wpa_eapol_key *key,
struct wpa_ptk *ptk)
{
size_t ptk_len = sm->pairwise_cipher == WPA_CIPHER_CCMP ? 48 : 64;
#ifdef CONFIG_IEEE80211R
if (wpa_key_mgmt_ft(sm->key_mgmt))
return wpa_derive_ptk_ft(sm, src_addr, key, ptk);
return wpa_derive_ptk_ft(sm, src_addr, key, ptk, ptk_len);
#endif /* CONFIG_IEEE80211R */
wpa_pmk_to_ptk(sm->pmk, sm->pmk_len, "Pairwise key expansion",
sm->own_addr, sm->bssid, sm->snonce, key->key_nonce,
(u8 *) ptk, sizeof(*ptk),
(u8 *) ptk, ptk_len,
wpa_key_mgmt_sha256(sm->key_mgmt));
return 0;
}

13
src/rsn_supp/wpa_ft.c
View file

@ -26,7 +26,7 @@
int wpa_derive_ptk_ft(struct wpa_sm *sm, const unsigned char *src_addr,
const struct wpa_eapol_key *key,
struct wpa_ptk *ptk)
struct wpa_ptk *ptk, size_t ptk_len)
{
u8 pmk_r1_name[WPA_PMK_NAME_LEN];
u8 ptk_name[WPA_PMK_NAME_LEN];
@ -51,8 +51,8 @@ int wpa_derive_ptk_ft(struct wpa_sm *sm, const unsigned char *src_addr,
wpa_hexdump(MSG_DEBUG, "FT: PMKR1Name", pmk_r1_name, WPA_PMK_NAME_LEN);
wpa_pmk_r1_to_ptk(sm->pmk_r1, sm->snonce, anonce, sm->own_addr,
sm->bssid, pmk_r1_name,
(u8 *) ptk, sizeof(*ptk), ptk_name);
wpa_hexdump_key(MSG_DEBUG, "FT: PTK", (u8 *) ptk, sizeof(*ptk));
(u8 *) ptk, ptk_len, ptk_name);
wpa_hexdump_key(MSG_DEBUG, "FT: PTK", (u8 *) ptk, ptk_len);
wpa_hexdump(MSG_DEBUG, "FT: PTKName", ptk_name, WPA_PMK_NAME_LEN);
return 0;
@ -520,7 +520,7 @@ int wpa_ft_process_response(struct wpa_sm *sm, const u8 *ies, size_t ies_len,
const u8 *ric_ies, size_t ric_ies_len)
{
u8 *ft_ies;
size_t ft_ies_len;
size_t ft_ies_len, ptk_len;
struct wpa_ft_ies parse;
struct rsn_mdie *mdie;
struct rsn_ftie *ftie;
@ -611,11 +611,12 @@ int wpa_ft_process_response(struct wpa_sm *sm, const u8 *ies, size_t ies_len,
sm->pmk_r1_name, WPA_PMK_NAME_LEN);
bssid = target_ap;
ptk_len = sm->pairwise_cipher == WPA_CIPHER_CCMP ? 48 : 64;
wpa_pmk_r1_to_ptk(sm->pmk_r1, sm->snonce, ftie->anonce, sm->own_addr,
bssid, sm->pmk_r1_name,
(u8 *) &sm->ptk, sizeof(sm->ptk), ptk_name);
(u8 *) &sm->ptk, ptk_len, ptk_name);
wpa_hexdump_key(MSG_DEBUG, "FT: PTK",
(u8 *) &sm->ptk, sizeof(sm->ptk));
(u8 *) &sm->ptk, ptk_len);
wpa_hexdump(MSG_DEBUG, "FT: PTKName", ptk_name, WPA_PMK_NAME_LEN);
ft_ies = wpa_ft_gen_req_ies(sm, &ft_ies_len, ftie->anonce,

2
src/rsn_supp/wpa_i.h
View file

@ -240,6 +240,6 @@ int wpa_supplicant_send_4_of_4(struct wpa_sm *sm, const unsigned char *dst,
int wpa_derive_ptk_ft(struct wpa_sm *sm, const unsigned char *src_addr,
const struct wpa_eapol_key *key,
struct wpa_ptk *ptk);
struct wpa_ptk *ptk, size_t ptk_len);
#endif /* WPA_I_H */